Thanks John, I may get a gripper to put to the end of my arm (although I may not use a gripper, still thinking about fun things to terminate the arm with - laserpointer, pen, hook etc), but the major fun will be in building the thing myself I think, although it's tempting to get parts and just assemble to get something working. 
I like the look of the hexapod robots though. I wonder how hard it is to control 18 servos from an arduino?